Vented or unvented hot water cylinder - upgrade Cost?

I'm doing a bathroom upgrade and am going to fit an Aqualisa Quartz digital shower.

At this stage would the pro's recommend changing my loft tank for 50 gallons + as I only have a 25 which isn't enough cold stored water and fitting pumped version of shower or changing my dhw cylinder for unvented and running mains pressure with unpumped shower?

For a non expert, does the second option mean sealed system CH and new boiler too or can open vented boiler run an unvented dhw cylinder?

Any and all advice appreciated cause it'll be a right problem getting a new loft tank in place.

Thanks.

can open vented boiler run an unvented dhw cylinder?

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It can, no issues there.
I assume you know unvented installers should be registered..

ChrisR said:

can open vented boiler run an unvented dhw cylinder?

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It can, no issues there.
I assume you know unvented installers should be registered..

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I didn't know, thanks. That just the sort of advice I'm here for.

Is that a plumbing registration rather than corgi or a specific part of corgi?

Can I also ask which route you'd recommend on my original question?

a person needs to be g3 registered to undertake the installation of an unvented hot water storage vessel that contains more than 15litres of water.

corgiman said:

a person needs to be g3 registered to undertake the installation of an unvented hot water storage vessel that contains more than 15litres of water.

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Thanks for that corgiman. Would you actually recommend an unvented cylinder though or fit a larger cold water tank and stay open vented?

I need to order the shower this week and don't know whether to get pumped or not.

Bit of a hard one to answer bit like chicken and the egg.

Fitted loads of quartz pumped and non pumped great bits of kit got one myself they are the dogs.

Problem is with the tank or tanks you will require the pumped version and it may quite quickly empty the tank unless the incoming main is up to the job, try working out how much water enters the tank in Litres per minute, either with a flow cup or drain the tank half way down and put a bucket of known capacity under the inlet and timing to see how many litres per minute flow there is.

That way it will tell you if your existing tank is up to the job or if you need another tank the rest is just simple maths. Like how many minutes can I shower before the tank runs dry and ruins the pump.

If it appears first time that you are on the low side try changing the float valve to a new one which could give you a few more Litres per min as the old one could be blocked or stuck partly shut, simple enough job could save you hundreds.

OTOH if you got the dosh stick in an unvented I get over 30LPM out of mine and that is a very exhiliarating shower

Try it youv'e nothing to loose.

ididdidi said:

OTOH if you got the dosh stick in an unvented I get over 30LPM out of mine and that is a very exhiliarating shower

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Thanks,

As a very rough approximation before I get a reg'd guy in, what would this likely cost? I've got what I consider a relatively straight forward airing cupboard plumbed in the normail way. Plumber can leave all the old stuff in the loft for me to remove. On top of that I'm in a bungalow so access to area above is easy.
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lynda, moderator

please note forum rule 9

Probably £1200 - £2000, depending.

Including the cyl.....If you`re near Guildford, a M8`s got the unvented ticket.

I'll be honest, I don't really want to spend that much.

I think I'll buy a 50 or 70 gallon circular loft tank and upgrade the cold water storage instead.

I've got other things around the house that need that sort of spend first.

Thanks anyway.